Lattice deformation of ZnO films with high nitrogen concentration

Nitrogen-doped ZnO/Al2O3 films grown at elevating temperatures (300–800 °C) have been investigated by plasma-assisted molecular beam epitaxy (P-MBE). High nitrogen concentration (∼1022 cm−3) is achieved in the films grown at relatively low growth temperature (<500 °C) range. High nitrogen concentration accompanies considerable degradation of crystallinity and residual tensile strain, which was evaluated by high resolution X-ray diffraction (HRXRD). The structural evolution is discussed in terms of the increase of complex defect density in the films. The ionization energy of acceptor was estimated as ∼140 meV from the excitation power dependence of donor–acceptor pair emission line by using low temperature (10 K) photoluminescence spectroscopy.